The present invention relates to a system for steering both front and rear wheels of a motor vehicle.
Such a system is, for example, disclosed in Japanese Patent Laid Open 59-26363, in which the rear wheels are rotatable about king pins in synchronism with the steering of the front wheels. In the prior art, the steering system for the rear wheels is operatively connected to the steering system of the front wheels by a mechanical transmitting system, so that the rear wheels are steered in dependency on the steering operation of the front wheels.
The steering direction and steering angle of the rear wheels are changed in accordance with the speed of the vehicle. For example, in a low vehicle speed range, the rear wheels are rotated about the king pins in a direction opposite to the direction of the front wheels, so that the vehicle can be turned at a small radius. At a high vehicle speed, the rear wheels are rotated in the same direction as the front wheels so as to improve the response to steering wheel operation by the driver.
Accordingly, the mechanical transmitting system must be provided with a change-speed device for changing the transmission ratio and a mechanism for changing the steering direction of the rear wheels. As a result, the system becomes very complicated in construction, large in size and expensive.